Study On Navigation Flow Condition In Common Lower Approach Channel Of Baishiyao Double-line Ship Lock

In the process of filling and releasing water in the locks,non-constant flow will be generated in the approach channel,causing water surface fluctuations and changes in flow velocity and flow pattern,while double or multi-line locks sharing the approach channel may cause reciprocal flow and local reverse flows,these phenomena will have a greater impact on lock operation,ship access and safe berthing,while the reverse head caused by filling and releasing water will have an impact on the operation of another line of locks herringbone gate.The reverse head caused by filling and releasing water will have an impact on the operation of the other line of ship gate.In order to ensure the safety of ships entering and leaving the lock and improve the navigable water flow conditions in the approach channel,scholars at home and abroad have conducted many related researches,but the research objects are mainly the single-line lock outlet energy dissipation facilities and the layout of the gate area at the mouth of the approach channel,and there are less researches on the influence of the arrangement of the main and deputy guide walls of the common approach channel of the double-line locks on the water flow conditions in the approach channel and the mutual influence between the two lines of locks.In this thesis,based on the expansion project of Baishiyao ship lock,a 1:30hydraulics physical model of the lower approach channel shared by the Baishiyao hub double-line ship lock is established,and the guide wall arrangement of the lower approach channel shared by the double-line ship lock is tested in multiple scenarios to reveal the influence of different lengths and different types of bulkheads on the water flow conditions in the lower approach channel,and the mutual influence of the shared approach channel of the double-line ship lock is studied for different operation modes of the double-line ship lock.The main research results are as follows The main research results are as follows.(1)For the double-line locks sharing the lower approach channel,the longitudinal flow velocity downstream of the corresponding lock is often larger when the water is released from the single-line lock,influenced by the width of the approach channel and the arrangement of the counseling wall,while the water flow in the downstream area of the other line lock is in the alternating state of dynamic and static water,and is usually accompanied by the reverse flow phenomenon due to the shearing effect of the downstream flow.(2)Appropriately shorten the length of the lower approach channel bulkhead between the two lines of locks,can make the water diffuse in advance,effectively reduce the longitudinal flow velocity of the lock mooring section on the discharge side,and improve the water flow condition of the lock mooring section on the discharge side.(3)For the shorter counseling wall and flow divider wall,the use of counseling wall permeability and flow divider wall open bottom hole,due to the shallow water depth of the lower approach channel,and from the energy dissipation work out of the flow after the flow velocity is large,the improvement of the water flow conditions in the approach channel is not obvious.If you need to take the above two measures,you need to increase the area of the permeable or open hole,so that the permeable area reaches a certain value.(4)There are various operation modes such as reverse operation,simultaneous operation and staggered operation of double-line locks.The experimental study shows that when the double-line locks are released at the same time,the water flow in the approach channel often has the superposition of the flow speed and water level,which has a greater impact on the driving and berthing of the locks in the approach channel;and the staggered discharge is affected by the total width of the approach channel and the reciprocal flow,and the navigation index in the approach channel is difficult to meet the requirements.Therefore,combined with the operating characteristics of the double-line locks,it is recommended that the double-line shared approach channel locks to take reverse operation,that is,a line upstream(water filling),a line downstream(water release)operation mode,the operation mode that can protect the navigation water flow conditions in the approach channel,but also does not affect the double-line locks through the capacity.